Cardiovascular disease update by Dr Bruno Jesuthasan

Cardiovascular disease (CVD) kills more Australians than any other disease group (37.6 per cent of all deaths in 2001) and affects 3.67 million Australians each year. In the coming decade the burden of cardiovascular disease is expected to increase due to the growing number of elderly Australians.

The proportion of adults with risk factors is high

• 60 per cent overweight
• 54 per cent not sufficiently active
• 51 per cent high cholesterol
• 30 per cent high blood pressure
• 20 per cent smoke daily
• 8 per cent diabetes mellitus

The risk profile in the Australian population is changing

• prevalence of obesity has doubled in the last 20 years
• prevalence of diabetes has doubled in the last 20 years
• prevalence of high cholesterol has not fallen over the last 20 years.

But there is some good news

• 50 per cent fall in the prevalence of high blood pressure since 1980’s
• 25 per cent fall in the incidence of coronary events in the last decade
• fall in the coronary heart disease deaths in hospital.

Asymptomatic adults should form the focus of our attention as approximately half of all coronary deaths are not preceded by cardiac symptoms or diagnosis. Coronary heart disease (CHD) has a long asymptomatic latent period and this provides an opportunity for early preventive measures.

Patients already at high risk of cardiovascular disease include

• diabetes and age > 60 years
• diabetes with microalbuminuria
• moderate or severe chronic kidney disease (estimated glomerular filtration rate < 45 mL/min/1.73 m2)
• a previous diagnosis of familial hypercholesterolaemia
• systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 110 mmHg
• serum total cholesterol > 7.5 mmol/L.

Cardiovascular tests for risk assessment in asymptomatic adults

• Resting ECG—reasonable for cardiovascular (CV) risk assessment in adults with hypertension or diabetes mellitus and may be considered in adults without hypertension or diabetes mellitus.
• Echocardiography (resting)—echocardiography to detect left ventricular hypertrophy may be considered in patients with hypertension. Not recommended for adults without hypertension. Left ventricular hypertrophy has been shown to be predictive of CV and all cause mortality independent of blood pressure.
• Exercise electrocardiography—may be considered for cardiovascular risk assessment in intermediate risk asymptomatic adults (particularly when attention is paid to non ECG markers such as exercise capacity).
• Stress Echocardiography—not indicated for CV risk assessment in low or intermediate risk asymptomatic adults.
• Myocardial perfusion imaging—not indicated for CV risk assessment in low or intermediate risk asymptomatic adults. May be considered for advanced CV risk assessment in patients with diabetes mellitus, strong family history of coronary artery disease (CAD) or previous risk assessment suggests high risk of CAD (e.g. coronary artery calcium score ≥ 400).
• CT for coronary calcium—reasonable for adults at intermediate risk. Not recommended for adults at low risk. Coronary calcium scoring is reasonable for cardiovascular risk assessment in diabetics over the age of 40 years.
• CT coronary angiography —not recommended for CV risk assessment in asymptomatic adults.

Management of high risk asymptomatic patients should include aggressive risk factor modification

• blood pressure control
• control of blood sugar levels in diabetics
• treatment of hyperlipidaemia
• cessation of smoking
• dietary modifications
• weight loss
• regular exercise.

Summary

• CVD is a significant health burden in our society.
• CVD has a long latent asymptomatic period.
• The cardiovascular risk is modifiable in majority of the patients.
• This provides the greatest opportunity for preventive measures.
• Absolute CVD risk assessment in asymptomatic adults may help in preventive measures.
• In asymptomatic adults main stay of management is aggressive risk factor control.

Dr Jesuthasan consults at Mater Private Hospital Redland. His interests include general cardiology, echocardiography, stress echocardiography and coronary angiography.

Reference

1. National Heart Foundation, 2004.
2. 2010 ACCF/AHA Guideline for assessment of cardiovascular risk in asymptomatic adults.